Efficient Production of 2-Keto-l-Gulonic Acid via One-Step Fermentation Using Gluconobacter oxydans WTF0512 and Ketogulonicigenium vulgare WTF0114.

Currently, the main method for producing the vitamin C precursor 2-keto-l-gulonic acid (2-KLG) is a two-step fermentation process, in which secondary sterilization and fermentation processes result in higher costs and energy consumption. Consequently, the development of a one-step fermentation process is seen as a more desirable approach for 2-KLG production. In this study, we used Gluconobacter oxydans WTF0512 and Ketogulonicigenium vulgare WTF0114 as co-cultured strains for the production of 2-KLG from d-sorbitol via one-step fermentation. The fermentation behaviors of G. oxydans WTF0512 and K. vulgare WTF0114 were initially investigated. Subsequently, the fermentation process and medium were optimized, and the titer of 2-KLG reached 132.99 ± 0.52 g/L, with a molar conversion rate of 92.42%, which, to the best of our knowledge, is the highest production via one-step fermentation reported to date. These findings will provide a basis for developing a more economical large-scale one-step fermentation process for the production of 2-KLG.